The full statement from Commissioner Margrethe Vestager in charge of competition policy read:

"Google has come up with many innovative products and services that have made a difference to our lives. That's a good thing. But Google's strategy for its comparison shopping service wasn't just about attracting customers by making its product better than those of its rivals.

"Instead, Google abused its market dominance as a search engine by promoting its own comparison shopping service in its search results, and demoting those of competitors."

"What Google has done is illegal under EU antitrust rules. It denied other companies the chance to compete on the merits and to innovate. And most importantly, it denied European consumers a genuine choice of services and the full benefits of innovation."

It gave the Mountain View, California, company 90 days to stop or face fines of up to 5 percent of the average daily worldwide turnover of parent company Alphabet.

The European Commission, which polices EU competition rules, alleges Google elevates its shopping service in search results and "demoted rival comparison shopping services" even when other options might have better deals.

The investigation conducted over 5.2 terabytes worth of search results, financial traffic data from competitors and surveys analysing the impact of visibility in search results.

The conclusive evidence showed: "the most highly ranked rival service appears on average only on page four of Google's search results, and others appear even further down. Google's own comparison shopping service is not subject to Google's generic search algorithms, including such demotions."

Google maintains it's trying to package its search results in a way that makes it easier for consumers to find what they want.

Two other cases of Google allegedly abusing its dominant position as a search engine being investigated by the European Commission include Android operating system stifling choice and innovation on mobile apps, as well as preventing third-party websites from sourcing search ads from competitors using AdSense.